1. Field of the Invention
The present invention relates, in general, to special effect lighting devices and systems such as those used to imitate or simulate flames from an actual fire, and, more particularly, to an assembly for generating thin sheets or planar displays of light that can be used to simulate flames when projected onto fabric flame elements that move or flow downstream of a fan, e.g., a special effect system for displaying fire or other lighting effects in a window and/or over large surfaces.
2. Relevant Background
There are many applications and uses for devices that simulate fire or the flames of a fire. For example, simulated flame devices or flame simulators are used in amusement parks to provide desired lighting and to create the illusion to people on a ride that they are passing fire. Simulated flames and fire is used in place of real fire to address safety and maintenance concerns. For example, the flame simulators may be provided as burning logs, torches held by ride characters or mounted on walls, and in situations calling for a large flame effect such as a burning window or building. Additionally, there is a growing trend toward the use of flame simulators in residential setting such as outdoor theme lighting, imitation logs burning in a fireplace, and the like.
A number of challenges face the designer of a flame simulator. There is a demand that the flame be realistic even from relatively short distances. Homeowners, amusement park operators, and other users also require that the flame simulators be very safe to use, be easy to maintain, and be relatively inexpensive. Existing flame simulators have not been able to effectively address all of these requirements, and there is a continuing demand for improved ways of producing a flame special effect.
One type of flame simulator uses a fabric flame element such as a silk flame element that is illuminated by a light source. To make the effect more realistic, air current or flow from a fan is directed over the flame element that can make produced “flame” appear to flicker. Unfortunately, there are a number of problems with using silk flame simulators especially in applications that require many hours of service such as in amusement parks and in outdoor residential and commercial lighting fixtures. Typical silk flame simulators use incandescent lighting to illuminate the flame elements. The bulbs have fairly short lives and need to be replaced regularly. In addition to replacement and maintenance issues, incandescent bulbs or lamps use significant amounts of energy and produce significant amounts of waste heat. Hence, the heat must be removed and/or the simulator has to be positioned in locations where it will not be contacted by people and flammable materials.
Standard silk flame elements are often not useful in larger displays such as those used for simulating flames in windows of a burning building (e.g., burning windows). Larger flame simulators generate significant amounts of heat that must be removed with air handlers and conditioning units that may be bulky and that are often expensive to operate and maintain. Some large flame simulation devices use incandescent or similar light sources that are masked or filtered to generate a thin sheet or plane of light that is projected onto fabric curtains or elements that are placed downstream of a fan or blower. In addition to generating unwanted heat, these devices often consume significant amounts of energy, such as thousands of Watts of energy for larger displays or systems. Many displays are operated many hours a day such as while an amusement park is open to the public. As a result, energy costs associated with existing large flame simulation devices can be quite high. Fiber optic systems have been created for producing light in a thin sheet, but these systems typically are very expensive and are often large and cumbersome making them inappropriate for applications requiring numerous simulators or having size restrictions.
Yet another problem with many flame simulators, including silk flame simulators, is the amount of extra unwanted light that passes by the flame (i.e., blow-by). Blow-by is a particular problem in dark, enclosed areas such as ride tunnels or chambers and can essentially destroy the overall look of the flame illusion that is produced by the flame simulator.
There continues to be a demand for innovative flame simulators. Preferably, such flame simulators will be easy to maintain, will produce less heat, will be inexpensive to manufacture, and will produce improved visual effects (i.e., more accurately represent flames of a fire to an observer).